1. Technical Field
Example embodiments of the present invention relate to load control of a mobile communication system, and more particularly, to a mobile communication system for distributed load control and a distributed load control method for use in the same that provide a machine-type communication (MTC) service.
2. Related Art
Although 3rd Generation Partnership Project (3GPP) mobile communication systems are securing competitiveness in current mobile communication services through high speed downlink packet access (HSDPA) having an extension of downlink (DL) capacity, and high speed uplink packet access (HSUPA) having an extension of uplink (UL) capacity, new radio access technology is required to secure competitiveness even in future mobile communication services according to rapidly growing information communication society.
For current 3GPP-related technology to have competitiveness in the future, radio access technology of next-generation mobile communication systems (international mobile communications (IMT)-advanced systems) should be significantly considered. Main issues of these next-generation mobile communication systems are reduced latency, higher user data rates, improved system capacity and coverage, cost reduction of a network provider, and the like.
In addition, the next-generation mobile communication system considers interworking and handover with a non-3GPP system such as a wireless local area network (WLAN) as well as interworking with a 3G mobile communication system. Next-generation mobile communication terminals are expected to include a function of simultaneously supporting WLAN and a 3GPP system. In particular, machine to machine (MTM) communication or machine-type communication (MTC) terminals are expected to be widely used for machine-to-human (MTH) communication and MTM communication, in addition to human-to-human communication.
To satisfy requirements and operating environments of the next-generation mobile communication systems as described above, a function of optimized, advanced, and efficient load control is required in the next-generation mobile communication systems.
In the mobile communication system, the load control function prevents the entire system from crashing, or prevents communication from being disconnected by carrying out an operation of limiting a connection or access according to a state when signaling is temporarily increased in each node of the mobile communication system and overload occurs, or when packet data exceeds capacity allowed for a base station and congestion occurs if there is a call setup request.
In general, a load control method is a method of limiting or rejecting a call setup request when overload occurs, a method of temporarily delaying or deleting processing of packet data, or the like.
Because an existing load control method is mainly used for a mobile communication system for human-to-human communication, overload does not largely occur. Accordingly, in the existing load control method, it is determined whether to accept and process a call in consideration of only resource management.
However, various types of multimedia services will be provided in the next-generation mobile communication systems, and the congestion of signaling and traffic is expected to occur due to the advent of MTC terminals. Accordingly, because the existing load control method may be unsuitable for the next-generation mobile communication systems, an optimized load control method for use in the next-generation mobile communication systems is required, but technical development for the optimized load control method is not sufficient.
Many studies have been conducted to allocate radio resources by assuming the same priority for all calls without considering various characteristics for user equipment (UE) services for use in human-to-human communication, or manage radio resources on the basis of received signal strength (RSS) of UE or its moving speed.
Although the studies of the related art as described above may improve the performance of the mobile communication system by efficiently employing limited radio resources having a significant influence on the performance in the mobile communication system, their application to the next-generation mobile communication systems is difficult.
Many studies of radio resource management and the like through buffers, priority, and fuzzy theory have been conducted. These methods are very simple and may not expect improved performance. A radio resource management algorithm based on the fuzzy theory is very complex and unsuitable for commercial systems because its actual implementation is not cost-effective.
Accordingly, there is a need for a load control method capable of reducing or preventing the congestion of signaling and traffic according to MTC service provided in the next-generation mobile communication systems.